Over so many decades man has made valiant efforts to replace completely the natural heart with an artificial one. The Jarvik-7 is one such design. It is bulky, driven by compressed air, and has a wheeled about control unit. It made headlines years ago when it was implanted into dentist, Dr. Schroader, who died after several months. Several improvements have been made on the original design. An Abiocor design was recently approved for trials in humans by the US Food and Drug Administration (FDA). This design showed some promise but was abruptly discontinued when some patients died after the devices unexpectedly failed. Meanwhile, the FDA again approved implantation of this device in some of the weakest heart patients who have less than 30 days to live. The Abiocor, nevertheless, is a considerable improvement over the Jarvik-7 albeit with still a great deal of hurdles to overcome. There have been other attempts to meet this challenge, but with little or no success. Replacing the natural heart with a properly functioning artificial heart that can truly prolong human life is indeed a daunting task.
Several problems plague these aforementioned designs. They include, but are not limited to, bulkiness, difficulty being miniaturized into different sizes to fit individuals of various sizes. They usually do not communicate with the brain as the natural one does via the nerves, and as such do not vary frequency of beats and contractile force among other variables, as well as eliciting life-threatening thrombogenic events. Also, battery size and operating life is another major problem. Ventricular Assist Devices (VAD) have proven effective in some instances, but they only aid the natural heart and are not truly capable of replacing it.
The natural heart with its myriad of capabilities which includes the ability to continuously communicate with the brain, can be considered an “active” pump, while the above aforesaid artificial designs can be classified as strictly “passive” pumps. Essentially, this is the difference between active and passive functionality of natural and man-made body systems.